Rust preventive



Patented Apr. 1, 1952 UNITED STATES PATENT OFFICE 7 Leonard E. James .W.

Hand, Jr., Summit, N. J assignors to Standard' Oil Development Company,a corporation of Delaware N o Drawing. Application January 21, 1949,

Serial N0. 72,099

Claims. (01. 44-69) This present invention relates to a process forinhibiting therusting of metal surfaces, particularly when said metalsurfaces are stored or otherwise idle. A further object ofthis inventionis to contact the metal surfaces of an internal combustion engine with afuel composition comprising gasoline containing tetraethyl lead with anorganic halide which of itself is incapable of preventing rust, inadmixture with oil soluble alkyl diamines as rust inhibitors. A morespecific object of the present invention is to inhibit rust formation onthe metal surfaces of an internal combustion engine, utilizing agasoline containing tetraethyl lead and an organic halide in admixturewith a lower alkyl diamine such as an ethylene, propylene, butylene oramylene diamine.

It is well known in the art to employ as fuels for'internal combustionengines, gasolines' containing tetraethyl lead and an added organichalide which functions as ascavenger agent for the lead. Internalcombustion engines utilizing fuels of this character tend to form ruston the interior surfaces, particularly when left idle. The rust formingtendencies are greatly aggravated in the presence of wet or moist air.The problem is particularly acute with respect to aviation engines wherethe normal practice is to have a turn-about period during which time theaviation engine is left in an idle condition. Furthermore, aviationengines are normally stored for periods of time prior to theirreinstallation in the plane. It is therefore, the object of the presentinvention to outline an improved process for taking internal combustionengines, especially aviation internal combustion engines out of service.

Various attempts have been mad to solve the problem of rust formation onthe metal surfaces of internal combustion engines. One method employedis to add various inhibitors to the lubricating oils utilized in theengine crankcases. These compounded lubricating oils, however, can onlycontact certain internal metallic areas of the engine. These oils, donot have ready access to certain internal surfaces of the engine,especially the upper section of the cylinder liner in and near thecombustion chamber, where the fuel enters. It is thus difiiculttoinhibit these particular sections against rust. Therefore, it is acommon and inconvenient practice to spray these sections through thespark plug holes with a compounded oil prior to storage. However,

neither complete coverage nor even distribution be attached to an of.the carbon atoms.

der liners and those metal parts of the engine to which only a fuelis'accessible. This is accomplished by adding to a fuel, such as;gasoline containing tetraethyl lead and an organic halide, an alkyldiamine. The loweralkyl diamines, as for example, the diaminescontaining.fro'm i2 to 5 carbon atoms, are especially suitable. These alkyldiaminesimay be added assingle compounds or as mixtures. For example,olefinic gaseous hydrocarbons containing from about 2 to.5 carbon atomsand taken from petroleum cracking operations may be halogenated and theproducts reacted with ammonia to form mixed diamines which areparticularly suitable. Of the single compounds, propylene diamine inparticular is preferred. I

The class of diamine addition agents of the present invention isrepresented by the following formula: H2NR-NH2, wherein R. represents analkyl group of straight or branched chain structure and containing from2-5 carbon atoms in the molecule. The amine groups may However, it ispreferred that these groups be attached to different carbon atoms whichare adjacent or are separated by not more than one carbon atom.

It has been found that these alkyl diamines when added to a fuel in aconcentration in the range from about 0.03 to 5.0%, preferably in theconcentration in the range from about 0.ll.0%, and said fuel compositionis passed through an engine prior to storage, the critical metallicsurfaces, including the cylinder liner area within the path of thepiston travel, are protected against the formation of rust. It will beunderstood that although it is generally preferred to utilize the fuelof the invention for running the engine for a short period of time justprior to storage, the fuel can be employed for running the engine innormal operations over extended periods of time. In this case,relatively small amounts of the diamine can be employed. However, theconcentration of diamine in the fuel should be greater than about 0.01%in order to obtain effective rust inhibition.

.In order to further illustrate the invention, the following example isgiven:

Example Various operations were conducted employing a one cylinderair-cooled Wisconsin internal combustion engine (AEH Motor). TheWisconsin engine had a cylinder made of nitrided steel (metal of thetype used in aircraft engines), an. aviation fuel having a clear octanenumber of and containing 3.9 cc. of tetraethyl lead per gallon andhaving the followin Engler distillation was used in the variousoperations:

The leaded octane number was 96 A. S. T. M. and 98 Research. A leadscavenger agent comprising ethylene di-bromide was added to the fuel ina concentration of one theory of halogen per theory of lead.

vThe operations were conducted in two stages. In the first stage of theoperation, the engine was run for 8 hours on the fuel composition. Inthesecond stage of the operation, the engine was dismantled and thecylinder placed in a humidity cabinet for 5 days. At the expiration of 5days, the extent rusting of the interior surface of the cylinder wasdetermined and recorded as per cent rusting."

In operation A the aviation fuel containin the above identified quantityof lead and lead scavenger agent was run as described. In operation Bthe identical fuel composition was run except that 0.1% of propylenedi-amine was used. The results of these operations are as follows:

It is evident that a substantial reduction in rust formation is securedby the composition of the present invention.

Having described the invention, it is claimed:

1; Improved leaded gasoline fuel which contains a lead scavenger agentand from about .03- 5% of an alkyl diamine selected from the class ofdiamines represented by the following formula: I-I2NR-NH2, wherein Rrepresents an alkyl group containing from 2-5 carbon atoms.

2. A fuel composition as defined by claim 1 wherein the concentration ofthe diamine is in the range from about .1-1%

3. A composition as defined by claim 2 wherein the amine groups areattached to carbon atoms which are not separated by more than one othercarbon atom.

4. The composition defined by claim 1 in which the said alkyl di-aminecomprises propylene diamine.

5. The composition defined by claim 1 in which the said alkyl di-aminecomprises a mixture of ell-amines containing from 2 to 5 carbon atoms.

LEONARD E. MOODY. JAB/[ES W. HAND, JR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,433,716 Smith et a1 Dec. 30,1947 2,447,615 Jones Aug. 24, 1948 2,496,444 Cook Feb. 7, 1950

1. IMPROVED LEADED GASOLINE FUEL WHICH CONTAINS A LEAD SCAVENGER AGENTAND FROM ABOUT .035% OF AN ALKYL DIAMINE SELECTED FROM THE CLASS OFDIAMINES REPRESENTED BY THE FOLLOWING FORMULA: H2N-R-NH2, WHEREIN RREPRESENTS AN ALKYL GROUP CONTAINING FROM 2-5 CARBON ATOMS.